Our biomedical goal is to better characterize the function of organs and synthetic tissue scaffolds (containing cells) by way of the nutrient transport characteristics of hierarchical arterial/venous, biliary and lymphatic vascular trees in organs or labyrinthine pore structures within scaffolds. Our bioengineering goals are to broaden the range of gray-scale accuracy of x-ray mu CT so as to more quantitatively characterize the microarchitecture of the hierarchical and labyrinthine systems in terms of their transport of solutes and cells and their mechanical function within those intact organs and within synthetic tissue scaffolds. This will involve development/evaluation and use of software to analyze and model the imaged transport channels and to enhance the image information content with tunable monochromatic x-ray scans, x-ray scatter imaging and new x-ray contrast materials (e.g.. nano-particulate) which are indicators of transport into/out of specific vascular or pore spaces of interest and by extending our cryostatic micro-CT capability so that the diffusional &micro-convective dynamics of contrast agent distribution can be followed by snap-freezing the specimens. AIM I: Characterize Solute Transport in Micro-Vascular "Trees" &Tissue Scaffold Pore "Labyrinths:" la) Segmentation &Dimensional geometry analysis of the "trees" and "labyrinths". Ib) Modeling of vascular "tree" and pore "Labyrinth" transport &transmission characteristics. Ic) Scaffold mechanical &pore transport properties relationship to tissue in-growth. AIM II: Micro-CT using Multi Energy and Scattered X-ray: lla) Multi-energy monochromatic x-ray will be evaluated for better discrimination of pathologically and metabolically accumulating compounds and lib) x-ray scatter imaging will be used to determine preferred diffusion paths in tendons and muscle. AIM III: Development &Evaluation of Nano-particulate Contrast Agent: Ilia) Biliary excretion and transport in polycystic liver disease. 1Mb) Lymph generation and transport. AIM IV: Generate a Web-Accessible Micro-CT Image Data Base: Place 3D image data sets in a web accessible data base so as to provide a range of micro-anatomic features available in various organs. AIM V: Develop an Image "Data Mining" Capability. Since the vast volume of data available in a micro- CT data set presents a great challenge to interrogate, we will implement interactive computer-graphics techniques suitable for extracting useful quantitative information from these data sets. The biomedical significance of these aims is their contribution towards increased understanding of transport mechanisms within synthetic implants, tissues and arterial walls in early stages of arterial disease, within biliary ductules in polycystic hepatorenal disease and spread of cells in lymphatic trees.